As a means of solving increasingly serious global warming and fossil energy depletion problems, a solar battery which is a power generation system using sunlight is attracting attention. Currently, a mainstream solar battery has a configuration in which solar battery cells having a monocrystalline or polycrystalline Si wafer are connected in series or in parallel, with electrodes and metal wiring members interposed therebetween. Usually, the connection of electrodes of solar battery cells and metal wiring members has been performed using an inexpensive solder exhibiting favorable conductive properties (Patent Literature 1). Recently, taking environmental problems into consideration, a method of covering copper wires, which are wiring members, with a Pb-free Sn—Ag—Cu solder, and heating them to a temperature equal to or higher than the melting temperature of the solder to connect electrodes of solar battery cells and wiring members has been known (Patent Literatures 1 and 2).
However, upon such a connection, since it is necessary to perform the heating at a temperature of 260° C. or higher that exceeds the melting point of the Sn—Ag—Cu solder, a problem is that warpage and cracking of the solar battery cells occur to thereby reduce yield. Recently, since there is a tendency of thinning a thickness of the solar battery cell for the purpose of reducing cost, a measure for preventing the warpage and cracking has urgently been demanded.
On the other hand, the use of conductive adhesives which are capable of electrical connection at a lower temperature has also been proposed (Patent Literatures 3 to 6). These conductive adhesives are compositions in which metal particles typified by silver particles are dispersed in a thermosetting resin, wherein the electrical connection is accomplished mainly by bringing the metal particles physically into contact with electrodes of solar battery cells and wiring members.